To lose weight and keep it off, you've gotta stick with it—Monday through Sunday. These tips make it a cinch.

There's something about weekends that sends caution—and calories—to the wind. Even if your workweek is all about smart snacks and sensible dinners, for many of us, all weight loss bets are off come 5 PM Friday, says clinical psychologist Robert Maurer, PhD, author of One Small Step Can Change Your Life. "It's almost like a dam bursting," he says. We're tired and feel like we've earned the right to put healthy weight loss habits on hold. A University of North Carolina at Chapel Hill study revealed that adults take in an extra 222 calories—nearly 15% of the number of calories an average woman needs each day—over the course of the weekend (including Friday).

Of course you want to live a little on the weekend, but if you're trying for weight loss, or even just keep the scale steady, you have to maintain a certain level of vigilance. Here, how to rethink your weekend habits so you'll lose weight all week.

WEEKEND THINK This week was tough; I deserve to splurge HEALTHIER SPURGE Splurge with extra savvy. The need for a reward is human nature, says Stephen Gullo, PhD, author of The Thin Commandments Diet. And for many, that "something special" is food. You can't change what makes you happy, but you can minimize the diet damage. Choose one portion-controlled item that requires you to leave the house, such as a cup of lobster bisque from your favorite eatery or a small, fresh pastry from the bakery. "It's more rewarding to have a nice treat than to waste calories on regular things you can have anytime, like potato chips or cookies," says Gullo. Doing something special works, too: Catch a movie, get a massage at the spa, or buy a flattering pair of yoga pants. (Check out 10 more little ways to indulge yourself with absolutely no guilt.)

WEEKEND THINK Eating and entertaining go hand in hand HEALTHIER SPURGE Plan some activities, not meals. When you eat with friends, you consume 50% more than you do alone, found a Pennsylvania State University study. Researchers suspect that it's not the food but a tendency to lengthen the meal to keep the good times going. Instead, shift your notion of fun to nonfood activities. You likely have a few favorites that don't involve eating—build on these until you shift the balance from drinks and dinner to window-shopping or visiting a new art exhibit. If you do want to grab a bite, stick to lunch—it's easier to eat light, and you probably won't order cocktails.

WEEKEND THINK I run around all week; now I just want to kick back HEALTHIER SPURGE Try a little active relaxation. Some decompressing is essential, but planting yourself on the couch for hours can lead to trouble. A long stretch of inactivity can inspire compulsive nibbling, especially if boredom is one of your overeating triggers, says Gullo. And the immobility quickly adds up: Skip your regular 1-mile walk, add those extra 222 calories you tend to eat on weekends—and that alone can equal a gain of about 7 pounds a year! Sure, you can indulge in afternoon channel surfing, but not all day long. Impose a time limit; 2 hours is fine. And use that extra time to do something good for yourself, like chopping veggies for dinner that night and snacks to take to work the next week. Also, don't forget to work downtime into your week so you don't feel as exhausted come the weekend.

WEEKEND THINK A predinner cocktail is par for the course HEALTHIER SPURGE Drink it during the meal. With fewer responsibilities and no early morning wake-up calls, even weekday teetotalers don't think twice about a cocktail before dinner—and then another while they eat. The problem: "Alcohol breaks down inhibitions, so it's harder to make healthy food choices when you do sit down," says Gary Foster, PhD, director of the Center for Obesity Research and Education at Temple University. A glass of Cabernet and a few handfuls of mixed nuts while making dinner or waiting to be seated can add up to more than 600 calories—and that's even before the appetizer. Instead, have the wine with your meal, and save added calories by swapping fries for veggies or sharing the lower-cal sorbet, not the chocolate cake. Choose high-quality drinks you'll want to savor, such as vintage wine or single malt scotch, over high-cal fruity concoctions, and sub in one or two club sodas with lime. (These 15 smarter cocktails and mocktails are a good place to start.)

WEEKEND THINK I'll just have one last hurrah before I start my diet on Monday HEALTHIER SPURGE Drop the "last supper" mindset. Healthy eating and weight loss doesn't have an on/off switch; it's a way of life, says Dave Grotto, RD, a spokesperson for the American Dietetic Association. He encourages his clients to treat themselves during the week, maybe with a light beer one night or a child's size ice cream cone another, so they're not feeling deprived and desperate enough to polish off a half-pint of ice cream on Friday night for 500 calories.) If you blow it, don't wait until Monday to get back on track; start your weight loss plan at your next meal or snack. Besides, giving yourself free rein on the weekend can reactivate negative eating patterns that are bound to carry over into the following week, says Gullo. Keep it up, and extra pounds are almost guaranteed.

WEEKEND THINK Obligations throw off my usual routineHEALTHIER SPURGE Take control—wherever and whenever you can. Between errands, quality time with the kids, grocery shopping, and household chores, your weekends are often too packed to accommodate your regular diet-and-exercise schedule. But part of developing healthy weight loss habits for life is about adapting, says Foster. It just takes a few adjustments: Toss a low-cal energy bar or apple into your purse before hitting the mall so you're not tempted by the food court; if you know you're going to be on the road all afternoon, have a later breakfast; or if restaurant reservations aren't until late, snack on string cheese and whole grain crackers to hold you over, and then order lean fish or meat and vegetables for dinner.

It's okay to shuffle around meals and snacks, just don't skip them or your hunger will overpower you, says Katherine Tallmadge, RD, author of Diet Simple. And plan active family outings that aren't doable during the week, such as a tennis match with your spouse or a hike with the kids. You burn slightly more calories than you would at your 9-to-5 desk job, which helps even out a sensible weekend splurge.